Members of the 3rd-Generation Partnership Project (3GPP) have developed specifications for the UTRAN (Universal Terrestrial Radio Access Network), which is the formal name for the radio access network of a Universal Mobile Telecommunications System (UMTS). Because the UTRAN is based on the use of Code-Division Multiple Access (CDMA) technology for the radio links between base stations and mobile terminals, the UTRAN is commonly referred to as a Wideband-CDMA (W-CDMA) network, and sometimes as Wireless Radio Access Networks (WRANs). The UTRAN consists of Radio Network Controllers (RNCs) and radio base stations (RBS's) that are referred to as NodeBs in 3GPP documentation. The NodeBs communicate wirelessly with mobile terminals, generally referred to as user equipment or UEs in 3GPP documentation, while RNC controls one or more of the NodeBs. The RNCs further provide connectivity to the Core Network (CN), which provides connectivity to public data networks such as the Internet.
Evolved UTRAN (E-UTRAN), also specified by the 3rd-Generation Partnership, is the evolution of the UTRAN towards a high-data rate, low-latency, and packet-optimized radio access network, and is commonly referred to as the Long-Term Evolution (LTE) wireless network. LTE networks use Orthogonal Frequency-Division Multiplexing (OFDM) in the downlink (transmissions from base station to mobile terminal) and Discrete Fourier Transform (DFT)—spread OFDM in the uplink (transmissions from mobile terminal to base station). The basic LTE downlink physical resource can thus be seen as a time-frequency grid, where each resource element corresponds to one OFDM subcarrier during one OFDM symbol interval. E-UTRAN consists of interconnected eNodeBs (evolved Node Bs) that are further connected to the Evolved Packet Core network (EPC). Because the eNodeBs include more functionality and are more autonomous in their operation than the NodeBs in UTRAN, RNCs are not needed in the E-UTRAN.
As currently deployed, LTE and WCDMA networks may have overlapping coverage areas, and may in some cases be operated by the same operators in a given region. However, these LTE and WCDMA networks generally operate separately, and generally do not interact with one another so as to optimize, in an intelligent manner, the allocation of network resources. This can lead to unnecessary degradations of network services and service outages.